Attaching photos/files best practice?

What’s the best practice to optimize storage use?

I see that images uploaded by users doesn’t automatically deleted to database when not in use. Even when a photo is attached to a thing, when I deleted the thing, the photo doesn’t automatically deleted to database. How can I optimize storage use for this?

Also, it seems that this option is not working?err

You can use scheduled workflows to delete objects that are no longer needed from your database. If you are finding that something is not working as expected, please submit a bug report.